Q&A #6466

Teachers' Lounge Discussion: Triangles

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From: Pat B

To: Teacher2Teacher Public Discussion
Date: 2003010710:32:12
Subject: Re: Given Lengths

One of those fundamental ideas that interfaces between common sense and geometry is that the shortest distance between two points is a straight line. In geometry this means that from A to B directly must be less than from A to C and then from C to B.... or in more direct language.. any two sides of a triangle must be greater than the third side.... You can condense this down to a simple test... if the two smaller sides add up to more than the largest side, then the three sides will form a triangle... The reasoning should be obvious.. imagine trying to make a triangle with three pieces of wood of lenghts 5, 10, and 20 inches... you lay the 20 inch piece down and nail the five inch to one end of it and the ten inch to the other end... now you need to nail the other end of the 5 inch piece to the ten inch piece, but when you swing them around, they aren't long enough to touch because 5+10 is less than the 20 inches they are apart... good luck -Pat Ballew, for the T2T service

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